@article{ELMA_1965__20_140803,
     author = {Helmut Hasse},
     title = {\"Uber mehrklassige, aber eingeschlechtige reell-quadratische {Zahlk\"orper.}},
     journal = {Elemente der Mathematik},
     pages = {49--59},
     publisher = {mathdoc},
     volume = {20},
     year = {1965},
     zbl = {0128.03502},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1965__20_140803/}
}